Chap 8: Nervous System - CNS III Flashcards
Extends from the foramen magnum to the 2nd
lumbar vertebra
SPINAL CORD
Two enlargements
cervical and lumbar
provide protection to the spinal cord and stability
Vertebral column and the meninges
tapered, lower end of the spinal cord where it
transitions into the cauda equina
Conus medullaris
thin, fibrous extension that anchors the
spinal cord to the coccyx
Filum terminale
bundle of spinal nerve roots that extends
from the conus medullaris
Cauda equina
Bigger than posterior median sulcus
Anterior median fissure
Center of spinal cord
GRAY MATTER
Looks like letter H or a butterfly
GRAY MATTER
Outer layer of spinal cord
WHITE MATTER
Contains myelinated fiber
WHITE MATTER
bundles of axons (white matter)
Tracts
Do not directly control volitional or
movements rather it helps in the fine-tuning
INDIRECT
Pyramidal tract – because they pass
through the pyramids
DIRECT
Muscle tone and skilled
movements, especially of
hands
Lateral corticospinal
Muscle tone and movement
of trunk muscles
Anterior corticospinal
Movement coordination
Rubrospinal
Posture adjustment,
especially during movement
Reticulospinal
Posture and balance
Vestibulospinal
Movement in response to
visual reflexes
Tectospinal
Pain, temperature, light
touch, pressure, tickle and
itch sensations
Spinothalamic
Proprioception, touch, deep
pressure and vibration
Dorsal column
Proprioception to cerebellum
Spinocerebellar (anterior
& posterior)
31 pairs; mixed nerves
SPINAL NERVES
Cervical
(C1-C8)
Thoracic
(T1-T12)
Lumbar
(L1-L5)
Sacral
(S1-S5)
Coccygeal
(1)
Connective tissue coverings of spinal nerves
Epineurium, perineurium and
endoneurium
For every bundle of the spinal
nerve, it is covered with
endoneurium
a bundle of fascicles
Epineurium
Formed by the anterior rami of C1-C5
CERVICAL PLEXUS
To supply a specific limb
Plexuses
important nerves from the cervical plexuses
Phrenic nerves
Spinal nerves branch and their branches are called
rami
Supplies the shoulders and upper limbs
BRACHIAL PLEXUS
a network of axons
Plexuses
Supplies the muscle for respiration
(diaphragm)
Phrenic nerves
Supplies the anterolateral abdominal wall, external
genitals, and part of the lower limbs
LUMBAR PLEXUS
Supplies the buttocks, perineum and lower limbs
SACRAL PLEXUS
Gives rise to the largest nerve in the body
SACRAL PLEXUS
The nerves arising from each region of the spinal
cord and vertebral column supply specific regions of
the body
DERMATOME
Supplies a small area of skin in the coccygeal
region
COCCYGEAL PLEXUS
Is the area of the skin supplied with sensory
innervation by a pair of spinal nerves
DERMATOME
Muscle innervation
Myotome
is an involuntary reaction in response to a
stimulus applied to the periphery and transmitted to
the CNS
REFLEXES
allow a person to react to stimuli more
quickly than is possible if conscious thought is
involved
REFLEXES
is the neuronal pathway by which a reflex
occurs and has five basic component
Reflex arc
Responds to a stimulus by produucing a
generator or receptor potential
Sensory receptors
Axon conducts impulses from integrating
center to effector
Motor neuron
Axon conducts impulses from receptor to
integrating center
Sensory neuron
One or more regions within the CNS that
relay impulses from sensory to motor
neurons
Interneurons
Muscle or gland that responds to motor
nerve impulses
Effector organ (muscles or glands)
The simplest reflex
STRETCH REFLEX
Is to remove a limb or another body part from a
painful stimulus
WITHDRAWAL REFLEX
Occurs when muscles contract in response to a
stretching force applied to them
STRETCH REFLEX
Will have autonomic ganglion
AUTONOMIC NERVOUS SYSTEM
interacted to the CNS
towards autonomic ganglia
Preganglionic
connected to the organ
Postganglionic
Primarily driven by neurotransmitter: Acetylcholine
(ACh)
CHOLINERGIC NEURON
Cholinergic receptors release
acetylcholine
Two types of Cholinergic receptors
▪ Nicotinic receptors
▪ Muscarinic receptors
Release norepinephrine (noradrenalin)
ADRENERGIC NEURONS
Two types of receptors (Adrenergic)
o Alpha receptors
o Beta receptors
Sympathetic
LOC. OF PREGANGLIONIC: T1-L2
LOC OF POSTGANGLIONIC: Collateral ganglia/ganglion chain
FUNCTION: fight or flight
a balance between the sympathetic
and parasympathetic activity
Autonomic tone
Parasympathetic
LOC. OF PREGANGLIONIC: CNS III, VII, IX, X and S2-S4
LOC OF POSTGANGLIONIC: Terminal ganglia
FUNCTION: rest or digest
Heart: Increases rate and force of contraction
SYMPATHETIC
Heart: Decreases rate
PARASYMPATHETIC
Blood vessels: Constricts and
dilates
SYMPATHETIC
Eyes: Dilates pupil, relaxes ciliary muscle to adjust lens for far vision
SYMPATHETIC
Eyes: Constricts pupil, relaxes ciliary muscle to adjust lens for near vision
PARASYMPATHETIC
Intestinal and stomach walls: Increases motility, relaxes sphincters
PARASYMPATHETIC
Liver: Synthesizes glycogen
PARASYMPATHETIC
Intestinal and stomach walls: Decreases motility, contracts sphincters
SYMPATHETIC
Adipose tissue: Breaks down
lipids
SYMPATHETIC
Liver: Breaks down glycogen, releases glucose
SYMPATHETIC
Adrenal gland: Secretes
epinephrine, norepinephrine
SYMPATHETIC
Sweat glands: Secretes sweat
SYMPATHETIC
Urinary bladder: Relaxes muscles, constricts sphincter
SYMPATHETIC
Salivary glands: Secretes thick
saliva
SYMPATHETIC
Salivary glands: Secretes watery
saliva
PARASYMPATHETIC
Urinary bladder: Contracts muscles, relaxes sphincter
PARASYMPATHETIC
Pancreas: Decreases secretion of digestive enzymes and insulin
SYMPATHETIC
Pancreas: Increases secretion of
digestive enzymes and insulin
PARASYMPATHETIC
is the major control and integration center of the ANS
Hypothalamus